Davey Johnson didn't know what exactly to expect when he arrived at Nationals Park Sunday morning. He had tried for weeks not to think about the fact his managerial career was nearing the finish line, focusing instead on the task of keeping his club alive in the NL playoff race as long as possible, despite the long odds this team faced.

So when his final day in uniform in Washington came and went Sunday, Johnson actually was surprised how much he enjoyed the experience, as draining as a pregame ceremony followed by a day-night doubleheader was for him.

"I was kind of dreading it, and then it was very pleasant," he said. "I was very moved by ownership and the front office and the fans and the players. ... It kind of wore me out."

So did a full afternoon and evening of baseball, one that saw the Nationals lose the opener to the Marlins 4-2 but then salvage a walk-off, 5-4 victory in the nightcap to keep their last-ditch hopes on life support for at least one more day.

Make no mistake, the Nationals' odds have just about gone kaput. But they haven't been pronounced dead quite yet. They trail both the Reds and Pirates by 5 games for the final Wild Card berth in the NL, with only 6 games remaining on the schedule.

A loss in St. Louis on Monday night, combined with wins by both Cincinnati and Pittsburgh, would officially eliminate the Nationals.

"I'm not good at math, but I'm good enough to know that losing makes it tougher," third baseman Ryan Zimmerman said following his team's afternoon defeat. "But you've just got to keep playing and see what happens. We put ourselves in this situation. We've just got to keep trying to finish strong."

The Nationals had a bit of extra motivation on Sunday, trying to celebrate their manager's D.C. farewell with a doubleheader sweep. But they slogged their way through an uninspired performance in the opener, falling behind 3-0 early and then unable to mount a late rally.

"We had to win pretty much every game going forward, which is really just a matter of the hole that we dug ourselves," said Dan Haren, who put the Nationals in that 3-0 hole via homers served up to Giancarlo Stanton and Christian Yelich. "We didn't play good baseball."

The Nationals played better baseball in the nightcap, though it was far from a perfect performance.

Stephen Strasburg, making his first start in 14 days following a bout of forearm tightness, was rusty from the time he took the mound. The right-hander gave up two quick runs and lasted only six innings, allowing three runs in total.

"He was actually awful," Johnson said, never one to mince words. "He was. I mean, every pitch he threw was up. He's got such great stuff, but everything was belt-high."

Strasburg admitted the rust factor may have played a role in his performance and admitted he perhaps had to set the bar a tad lower than he usually does on days he pitches.

"Not really get too frustrated," he said. "You're probably not going to have too good a feel of your pitches. Just go out there and try to be as effectively wild as you can."

Despite his struggles, Strasburg was in line to earn the win after the Nationals rallied to take the lead in the bottom of the sixth on Denard Span's two-run single. That lead, though, disappeared in the top of the eighth when Tyler Clippard allowed back-to-back doubles to Yelich and Stanton, leaving the game tied.

As it turned out, the Nationals had one final rally in them, just in the nick of time. Jayson Werth led off the bottom of the ninth with a double into the left-field corner. Pinch-runner Eury Perez then teamed up with Ian Desmond on a nifty double-steal to put the winning run only 90 feet away.

Up stepped Wilson Ramos, who hit a sharp chopper to third base, where Chris Coghlan booted the ball and couldn't get a handle on it before Perez crossed the plate to a roar from the few thousand fans who remained at the end of a home finale that had to be rescheduled following Saturday night's rainout.

"The first game was a little tough to swallow," said Ian Desmond, who became only the seventh shortstop in MLB history to post multiple 20-20 seasons. "But we bounced back. That's what's important."

And they gave their manager one last opportunity to walk off the home field a winner. As Johnson departed for the final time, he raised both arms out in celebration, smiled at the crowd and then ducked down the dugout tunnel.

His career isn't over quite yet. There are six more games to play in St. Louis and Arizona. And, should the unimaginable happen, he could yet find himself back at Nationals Park sometime next week, having guided his final club to a rally that would be even more improbable than the famous one he pulled off 27 years ago with the Mets.

"We ain't finished," Johnson said. "I take nothing for granted. I still think we've got a good shot. We need to win them all. Hey, I've been two runs down, one strike away and we came back. So don't lose the faith."